1. Field of the Invention
The present invention generally relates to an elevator control apparatus using a power storage apparatus.
2. Description of the Related Art
One conventional control apparatus of an elevator is indicated in FIG. 5. Referring now to a structural arrangement of FIG. 5, this conventional elevator control apparatus includes a motor 2, such as an induction motor, coupled to a commercial AC power supply 1 (referred to as a xe2x80x9ccommercial power supplyxe2x80x9d hereinafter), a drive machine 3, a rope 4, a car 5 of the elevator, and a balance weight 6. Both the elevator car 5 and the balance weight 6 connected to opposite ends of the rope 4 can be elevated by rotary-driving this drive machine 3. As a result, passengers in the elevator car 5 can be conveyed to a predetermined floor.
In FIG. 5, reference numeral 8 shows a controller. The controller 8 determines starting/stopping of the elevator, and produces a position/speed instruction of this elevator. Reference numeral 11 indicates a converter which is constructed of a diode and the like. This converter 11 rectifies AC electric power supplied from the commercial power supply 1 to produce DC electric power. Reference numeral 15 represents an inverter which is constructed of a transistor, an IGBT (Insulated-Gate Bipolar Transistor), and the like. This inverter 15 inverts the DC electric power converted by the converter 11 into AC electric power having a variable AC voltage and a variable AC frequency. Reference numeral 16 shows a regenerative resistor. This regenerative registor 16 is connected to a bus line existing between the converter 11 and the inverter 15. Also, reference numeral 17 indicates a regenerative resistor control circuit which is connected to both the regenerative resistor 16 and the bus line.
The above-explained balance weight 6 of the elevator is designed to be balanced when the properly-selected number of passengers get into the elevator car 5. As this properly-selected number of passengers, for example, half of the a capacity of this car 5 may be selected. Now, in such a case that the entire weight of the car 5 into which this properly-selected number of passengers gets is balanced with the balance weight 6, operation of this elevator (car 5) will now be considered. When this elevator is accelerated, the speed of this elevator is increased while this elevator consumes the electric power supplied from the commercial power supply 1. Conversely, when the elevator is decelerated, the speed of this elevator is decreased while returning the stored kinetic energy to the corresponding electric power supply. In this case, such an elevator operation in which a speed of this elevator is increased while consuming electric power supplied from this commercial power supply 1 is referred to as a xe2x80x9cpowering operation.xe2x80x9d Also, such an elevator operation in which a speed of this elevator is decreased while returning kinetic energy to electric power is referred to as xe2x80x9cregenerative operation.xe2x80x9dThe electric power produced by this regenerative operation is converted into thermal energy by both the regenerative resistor 16 and the regenerative resistor control circuit 17 so as to be consumed.
Also, reference numeral 7 shows an encoder which is provided on the drive machine 3. Reference numeral 12 indicates a current detecting apparatus. This current detecting apparatus 12 is provided between the motor 2 and the inverter 15. Reference numeral 13 indicates an inverter control circuit which is connected to the encoder 7, the controller 8, and the current detecting apparatus 12. Reference numeral 14 indicates a gate drive circuit which is connected to both the inverter control circuit 13 and the inverter 15.
In response to the instruction issued from the controller 8, the inverter control circuit 13 rotary-drives the motor 2 based on both the current feedback from the current detecting apparatus 12 and the speed feedback from the encoder 7 mounted on the drive machine 3, so that this inverter control circuit 13 can realize both positional and speed control of the elevator. Also, the inverter control circuit 13 controls the output voltage and frequency the inverter 15 via the gate drive circuit 14.
The conventional elevator control apparatus continuously receives the supply of electric power from the commercial power supply 1 to operate this elevator irrespective of degree of power demands. For example, peak electric power is required in the afternoon of summer time. During this time period, total power consumption is wanted to be reduced. However, the conventional elevator control apparatus can hardly reduce total power consumption during such a peak power-consumption time period.
As previously explained, since the electric power is consumed in synchronization with the elevator operation in the conventional elevator control apparatus, total power consumption during the peak power-consumption time period cannot be reduced.
The present invention has been made to solve the above-explained problems, and therefore, has an object to provide an elevator control apparatus reducing total power consumption of a commercial power supply during, for instance, a peak power-consumption-time period.
An elevator control apparatus, according to an aspect of the present invention, is comprised of: a converter for rectifying AC electric power to be converted into DC electric power; an inverter for inverting the DC electric power into AC electric power having a variable voltage and a variable frequency; a motor driven by the AC electric power having the variable voltage and the variable frequency so as to operate an elevator; a power storage apparatus for charging thereinto DC electric power; and charge/discharge control means for controlling charging/discharging operation with respect to the power storage apparatus based upon a charging target value every time with respect to the power storage apparatus.
Also, the charging target value owned by the elevator control apparatus of the present invention is set as follows: a target value during a peak power-consumption time period is set to be a small value in order that a total power consumption during such a peak power-consumption time period can be reduced.
Also, the charging target value owned by the elevator control apparatus, according to the present invention, corresponds to such a charging amount by which at least the elevator is operable in an emergency case.
Also, according to the elevator control apparatus of the present invention, in such a case that a charging amount of the power storage apparatus is smaller than the charging target value, the discharging operation from the power storage apparatus is stopped.
Furthermore, according to the elevator control apparatus of the present invention, when the elevator is stopped, the power storage apparatus is charged by using electric power supplied from a commercial power supply.
Also, according to the elevator control apparatus of the present invention, when the power storage apparatus is charged by using the electric power supplied from a commercial power supply, a current value of the commercial power supply is limited.